Vanity Mirror Lamps
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
The vanity mirror lamps activate when the mirror cover is open. The vanity mirror has a switch that closes when the mirror cover is open, providing ground to the lamps. The switch opens when the mirror cover is closed. The switch receives ground through G302.
Power to the vanity mirror is provided by the BCM through the courtesy lamps supply voltage circuit, so that they are protected by the inadvertent load protection in case that a mirror cover is left open.